Diffuse Mesothelioma - Diagnostic Criteria using Exfoliative Cytology

Our plain-English summary of Diffuse Mesothelioma - Diagnostic Criteria using Exfoliative Cytology, by E.B. Butler, A.V. Berry (1973).

The study

• Authors: E.B. Butler, A.V. Berry
• Published: BIOLOGICAL EFFECTS OF ASBESTOS (J.C. WAGNER, EDITOR), LYON: IARC SCIENTIFIC PUBLICATIONS, VOLUME 8, PP. 68-73 (1973)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This study by two cytologists examined fluid from the chest (pleural fluid) or abdomen (ascitic fluid) of patients with malignant mesothelioma. The aim was to see whether the tumour could be recognised from the cells it sheds into that fluid. The study used pleural fluid from 22 cases seen in Johannesburg since 1962 and fluid from British cases received in Manchester since 1968. These were compared with fluid from patients with benign mesothelial reaction and from patients with metastatic carcinoma. All diagnoses were confirmed by tissue examination (histology). The authors described four cell patterns and the cell features that separate malignant mesothelial cells from benign ones and from carcinoma cells. Special stains and enzyme tests showed no distinctive pattern. In the British series, cytology identified 25 of 27 mesothelioma cases. One of the remaining two specimens had no cells, and the other was read as a benign reaction. Of 30 carcinomas, 2 were wrongly called mesothelioma. Six fluids from patients with asbestos contact and symptomless effusions contained atypical cells, but none of these cases was confirmed histologically. The authors concluded that diagnosis by exfoliative cytology is possible and that special stains do not contribute.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Diagnostic cytology study comparing fluid specimens from histologically confirmed malignant mesothelioma with specimens from mesothelial reaction and metastatic carcinoma
• Who was studied: Pleural fluid from 22 malignant mesothelioma cases at the South African Institute for Medical Research (since 1962), compared with 25 mesothelial reaction and 25 metastatic adenocarcinoma cases. Pleural or ascitic fluid from British mesothelioma cases sent to Manchester from several UK centres (since 1968), compared with 21 mesothelial reaction and 30 metastatic carcinoma cases. South Africa: 15 men and 7 women, aged 41 to 67. Britain: 21 men and 6 women, aged 32 to 79. All patients were Caucasian except one African Bantu.
• Exposure: Asbestos exposure was not studied. Fiber types were not named. Six specimens came from patients with asymptomatic pleural effusion and a history of contact with asbestos.
• Main results:
  • Four cell patterns were seen in mesothelioma fluids: papillary pleomorphic (South Africa 8, Britain 4), papillary non-pleomorphic (South Africa 3, Britain 3), mixed (South Africa 8, Britain 11) and mainly single cells (South Africa 3, Britain 8). The frequencies differed between the two countries.
  • Among British cases with more than one specimen, 3 out of 6 showed a change of pattern from one specimen to another.
  • Bizarre nuclei, markedly irregular in shape and size, were noted in 24 of the 30 British carcinoma cases and much less often in mesothelioma cases.
  • No staining pattern distinguished mesothelioma. In British cases, a positive PAS reaction after diastase was seen in 6 of 24 mesotheliomas versus 10 of 25 adenocarcinomas, and a positive mucicarmine reaction in 1 of 16 mesotheliomas versus 3 of 13 adenocarcinomas.
  • Enzyme tests were described by the authors as almost equally unrewarding. Malignant mesothelial and carcinoma cells were negative for 5-nucleotidase, while 2 out of 4 mesothelial reaction cases were positive. Only half of the mesothelioma cases were positive for isocitric dehydrogenase, while all carcinoma and mesothelial reaction cases were positive.
  • British series, 27 histologically confirmed mesotheliomas: cytology diagnosed 25 as mesothelioma. One specimen was acellular, and the one missed case was read as mesothelial reaction.
  • British series, 30 carcinomas: cytology diagnosed 28 as carcinoma and 2 as mesothelioma. The 2 misdiagnosed cases were both anaplastic carcinomas of the lung.
  • British series, 21 cases of mesothelial reaction: 19 were correctly diagnosed by cytology and 1 was called mesothelioma.
  • Three fluids from cases clinically thought to be mesothelioma were correctly shown by cytology to be metastatic carcinoma. In three cases where mesothelioma was not suspected, cytology made that diagnosis.
  • The six fluids from asymptomatic patients with asbestos contact contained atypical macrophage-like cells similar to those found in proven mesothelioma. Two of these patients were later considered to show clinical evidence of malignant mesothelioma.
• The authors' conclusion: The authors concluded that diagnosing malignant mesothelioma by exfoliative cytology is possible. In their view, it depends mainly on recognising cells with mesothelial cytoplasmic features and malignant nuclei. They found that cell patterns help somewhat, cell blocks make distinctive features clearer, and special stains do not contribute.
• Limitations the authors state:
  • The six cases with asbestos contact and asymptomatic effusion were not confirmed histologically and were excluded from the survey.
  • Streptococcal hyaluronidase could not be obtained, so the most specific available stain for hyaluronic acid had to be used instead.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Cytology, Carcinoma, Histology, Mesothelial Cells.

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